Physics Forums (http://www.physicsforums.com/index.php)
-   Earth (http://www.physicsforums.com/forumdisplay.php?f=84)

 wolram Nov30-07 05:35 PM

Geothermal energy

Helium isotopes point to the best sources of geothermal energy
Unknown to most, the US has enough geothermal energy below its surface to supply three times the amount of energy that the US consumes annually. Up until this point no one has tapped this source because finding the geothermal hot spots is too expensive. Recently researchers discovered that surface indicators can predict if geothermal energy sources are below the ground -- now no more expensive drilling is required.

 wolram Dec2-07 12:22 AM

I see no one has disputed the above, so what is the problem, why are you not drilling away like crazy?

 russ_watters Dec2-07 08:53 AM

I'd like to see the math behind the "3000 times" (not three times) claim. That's an awful lot. Regardless, the article doesn't actually say anything about geothermal's viability in the US. It doesn't sound like they've actually tested the method and it doesn't say how far you have to drill. It's an interesting litte research project, but it isn't something that would cause people to start "drilling away like crazy."

 jim mcnamara Dec3-07 09:18 AM

This is not my discpline, but I see the same stuff in areas I do know - 'why don't we<...>'
questions based on one paper from one researcher.

<...> is usually pretty much in this order:
'cure cancer'
'stop global warming'
'create eternal life'
'cure aids'

The assumption you should make, which russ made without mentioning it: 'am I so much more informed on this subject than the 500 PhD's in the field who read the study before me'? Most of the time you should assume 'I am not'.

And in many case these unseen experts are doing one or more of these without our help:

1. pursuing it like crazy, getting investors, etc.
2. doing nothing because they know better
3. waiting for better data, or better more conclusive studies.
4. doing some research on their own

Drilling's expensive ya know. And there really is no global conspiracy preventing a geologist from becoming the Bill Gates of Geotherm, Inc. The people at eurekalert.org ought to know better too.

 Bystander Dec3-07 10:52 AM

Quote:
 Quote by russ_watters (Post 1525291) I'd like to see the math behind the "3000 times" (not three times) claim. That's an awful lot. Regardless, the article doesn't actually say anything about geothermal's viability in the US. It doesn't sound like they've actually tested the method and it doesn't say how far you have to drill. It's an interesting litte research project, but it isn't something that would cause people to start "drilling away like crazy."
"It has been estimated that within the continental United States, there is a sizable resource of accessible geothermal energy – about 3,000 times the current annual U.S. consumption." --- Nikki Staab, MEDIA CONTACT, ASU. What's the source of the estimate? Integrate the temperature gradient from earth surface to a depth of 2-3 km and multiply by 4MJ/(m3K) over 107 km2; the qualification regarding quality of the energy (99+% at less than 20 K above ambient, or, useless) is omitted.

 LURCH Dec3-07 12:34 PM

Quote:
 Quote by Bystander (Post 1526671) "It has been estimated that within the continental United States, there is a sizable resource of accessible geothermal energy – about 3,000 times the current annual U.S. consumption." --- Nikki Staab, MEDIA CONTACT, ASU. What's the source of the estimate? Integrate the temperature gradient from earth surface to a depth of 2-3 km and multiply by 4MJ/(m3K) over 107 km2; the qualification regarding quality of the energy (99+% at less than 20 K above ambient, or, useless) is omitted.
Does that assume removing all heat from the rocks underneath the entire landmass of the continental U.S.? I'm sure much of the world would applaud such a plan, but I cannot endorse it myself.

 Astronuc Dec5-08 07:41 PM

Re: Geothermal energy

Update:

Google is funding research in Geothermal Energy

Quote:
 Google.org has made the following grants and investments to help advance EGS: Potter Drilling: $4 million investment in two tranches focused on developing breakthrough hard rock drilling technologies for EGS. AltaRock Energy, Inc:$6.25 million investment in EGS technologies and project development to support the advancement of enhanced geothermal systems. Southern Methodist University Geothermal Lab: \$489,521 grant to improve geothermal resource assessment techniques and update the Geothermal Map of North America.

Engineered Geothermal Systems (EGS)
http://www.potterdrilling.com/geothermal-energy/egs/
Quote:
 An Engineered Geothermal System (EGS) is different from a naturally occurring hydrothermal system used to generate geothermal power today. Engineered Geothermal Systems are man-made and may be developed anywhere that hot impermeable rock exists. The EGS concept, originally know as Hot Dry Rock (HDR), was pioneered and patented in the early 1970s at Los Alamos National Laboratory (LANL) by Potter Drilling cofounder Bob Potter and his coworkers. EGS is one of the few sources of renewable energy with the promise of solving the increasing global demand for energy while addressing climate-change issues—and doing so for a price that is competitive with coal.
Hot Dry Rock Geothermal Energy Technology
http://www.lanl.gov/source/orgs/ees/...ther/hdr.shtml

The Future of Geothermal Energy
http://www1.eere.energy.gov/geotherm...eothermal.html
Quote:
 Recent national focus on the value of increasing our supply of indigenous, renewable energy underscores the need for reevaluating all alternatives, particularly those that are large and well distributed nationally. This analysis will help determine how we can enlarge and diversify the portfolio of options we should be vigorously pursuing. One such option that is often ignored is geothermal energy, produced from both conventional hydrothermal and Enhanced (or engineered) Geothermal Systems (EGS). An 18-member assessment panel was assembled in September 2005 to evaluate the technical and economic feasibility of EGS becoming a major supplier of primary energy for U.S. base-load generation capacity by 2050. This report documents the work of the panel at three separate levels of detail.

 Evo Dec5-08 08:19 PM

Re: Geothermal energy

So they are now hoping to get in on alternative energy sources eh? They certainly have enough capital.

 matthyaouw Dec5-08 09:15 PM

Re: Geothermal energy

The figure of 3x the USA's energy use is a bit suspect for me. How do they work that out? Is that the total heatflow for the whole continent? It reminds me of the often heard statistic that the earth recieves enough sunlight in x minutes to power the world for a year. True, maybe, but there is no way at all that it will ever be possible to tap all of even most of that energy.

 Astronuc Dec5-08 10:01 PM

Re: Geothermal energy

Quote:
 Quote by Evo (Post 1989441) So they are now hoping to get in on alternative energy sources eh? They certainly have enough capital.
It's part of Google's initiative on renewable energy.